Art of hydrocarbon oil conversion



Oct. 6, 1936. c, P. DUBBS ART OF HYDROCARBON OIL CONVERSION OriginalFiled March '7, 1927 III MQ NW Patented Oct. 6, 1936 UNITED STATESPATENT OFFICE Carbon P. Duhbs,

Wilmette, Ill., assigner, by,

mesne assignments, to Universal Oil Products Company, Chicago, Ill.,

Ware

a corporation of Dela- Application March 7, 1927, Serial No. 173,268

Renewed March 24, 1934 8 Claims.

The present improvements relate more particularly to a process andapparatus primarily designedl toeffect conversion of hydrocarbon oilsof' high boiling point range into hydrocarbons of lower'boiling pointrange suitable for commercial use.

The invention in its broad aspects embraces a process and apparatus forsimultaneously topping crude oil and subjecting the topped crude tocracking conditions of temperature and superatmospheric pressure.

The invention is characterized by its adaptability, iiexibility, andeconomy. The arrangement isv such that the process can be operated toproduce maximum yields of condensed overhead products, such asgasolineand the like, with a minimum production of non-vaporous residue, or theprocess may be operated to produce a minimum yield of light overheadproducts and a maximum yield of non-vaporous products, including all ofthe range between these two alternatives.

The invention is also characterized by the fact that the process may beso operated as to efciently work on any type of charging stock includedin a range from a low gravity heavy viscous residue up to. and includinga kerosene-.like charging stock having a Baume gravity of more or less.

As a feature of the invention, the charging stock is subjected to apreheating temperature by being caused to pass through a closed circuit,thus causing vaporization of the real light constituents of saidcharging stock. These vapors are permitted to be released, andseparately condensed and collected. That portion of the charging stockwhich does not vapcrize due to this preheating is then subjected tocracking conditions of temperature and superatmospheric pressure tocause substantial conversion and separation of vapors. The utility ofthe invention as well as many other objects and advantages will be moreapparent from the following description.

The single figure in the drawing designates a diagrammatic iiow chart ofthe invention.

Referring more in detail to the drawing, I designates a crude oilstorage receptacle from which o-il is passed through the line 2 in whichmay be interposed the pump 3 and meter 4 to the coil 5 mounted in heatexchanger E connected by branches 1 controlled by valves 8. Or thispreheater may be by-passed by closing valves 8 and opening the valve 9in the line ID. The charging stock may be then passed through the closedcoil II mounted in the heat exchanger I2 through the branches I3controlled by valves I4, or by closing the valves I4 the coil Il may bebypassed, and the oil passed throughV the line I5 controlled by valve I6communicating with line I1. The line I1 may communicate with the closedcoil I8 mounted in the upper portion of a dephlegmator I9 by means ofthe branches 20 controlled by valves 2|. Or the closed coil I8 may beby-passed by passing the oil through the by-pass line 22 which -iscontrolled by valve 23. The oil in either event passes into the line 24and into the water separator 25.

The desirability of subjecting the crude oil to the various preheatingsteps will be basedI upon the conditions of operation, gravity andcharacteristics of charging stock and products desired. Where the crudeoil contains water, it Will be advisable to subject it to one or more ofthe preheating stages illustrated, so that the temperature of the crudeby the time it reaches the water separator will be around, say 250 to400 F. Water which may separate in the water separator 25 may bewithdrawn through the line 26' controlled by valve 21. The crude passesout through the line 28 and may pass through the closed coil 29 mountedin preheater 30 through the branches 3I controlled by valves 32, or thecrude may be by-passed by opening valve 33 in line 34. VThe crude maythen pass through the line 35 controlled by valve 36 being introducedinto a vapor separator 31. This vapor separator 31 in the presentinvention may preferably take the form of a fractionating columnprovided with the usual bafes. The vapors which have formed due to thepreheating steps, separate in the vapor separator, and those whichremain uncondensed after passage through the vapor separator pass outthrough the vapor outlet line 38 through heat exchanger 6, condenser 39,collecting as a liquid in the receiver 40. This receiver 40 may beequipped with the usual uncondensable gas relief pipe 4I controlled byvalve 42, and with a liquid draw off pipe 43 controlled by valve 44. Forthe purpose of assisting in the fractionation of the vapors separatingin the vapor separator 31, a controlledY quantity of the liquidcollected in the receiver may be returned through the line 15in whichmay be interposed a pump 46 and valve 41, the line 45 discharging intothe topV of the vapor separator 31.

From the foregoing it will be apparent that I have utilized the wasteheat from the cracking system for the purpose, of vaporizing the lighterfractions contained in the crude oil, which lighter fractions arevaporized, separated, fractionated,

and those remaining uncondensed collected separately in the receiver'40.

The topped crude collecting in the lower portion of the vapor separator31 is withdrawn through the line 48, in which may be interposed a hotoil pump 49 and valve 50, being forced through the heating tube 5|mounted in the furnace 52 where it is raised to a conversion temperatureof, say '750 to 950 F. The heated oil from the heating tube 5| passesout through transfer line 53 in which may be interposed a Valve 54discharging into a reaction chamber 55 where vapor separation ispermitted to take place. The vapors separated in reaction chamber 55 maypass out through Vapor outlet pipe 56, in which may be interposed avalve 51, being introduced into a compartment 58 in thedephlegmator I9,defined by partitions 59 and 60. These vapors pass upwardly through theopen ended uprights 6| discharging into the interior of the dephlegInator |9. The dephlegmator I9 is provided with the usual bailles, pans,or the like. Reflux condensate preferably collectsyas indicated, in apool 62 surrounding the uprights 6|. The arrangement is such that theheat of the vapors passing upwardly through theV uprights 6| strips thereflux condensate in the pool 62 of the light fractions which may beentrained therein, due to the reboiling action which takes place. VThevapors remaining uncondensed after passage through the dephlegmator |79pass out through the vapor outlet pipe 63 controlled by valve 64,through heat exchanger |2, condenser 65, collecting in receiver 66 asliquid condensate. The receiver 66 is provided with the usual gas reliefpipe 61 controlled by valve 68, andwith the liquid draw offpipe 69controlled by valve 10.

Regulated portions of the distillate collecting lin the receiver 66maybe returned through the line 1| in which may'be interposed a pump 12 andvalve 13, to the upper portion of the dephlegmator I9. Y

In one method of operation, the valve 51 in the vapor transfer line 56from reaction chamber 55 tothe dephlegmator I9 is a pressure reducingValve whereby the pressure maintained on the Vheating tube 5| andchamber 55 is reduced or released altogether. Y

- The non-.vaporous residue may be withdrawn from the reaction chamber55 through any of the draw oif lines 14 controlled by valve 15discharging into the common header 16. To assist in the Withdrawal ofthis residue and to prevent the Vaccumulation of Ysubstantial quantitiesof coke or coke-like material in the chamber 55, an agitatorV designateddiagrammatically at 11 and which may be operated by the motor 18 may beprovided. All or any regulated portion of the residue passing throughthe residue draw off line 16 may be diverted into the line 19 controlledby valve 80, which'line 19 communicates with the heat exchanger 30,Vfrom which it discharges into the line 8|, further cooling the residuebyY means of the instrumentality 82, said residue being finallycollected in the residue storage receptacle 83.

All or Vregulated portions of the residue pass- Ving through the line 16may be diverted through the line 84 controlled by valve 8,5 into theinterior of a flash chamber 86. In the drawing the dephlegmator 9 andash chamber 86 are illustrated as one instrumentality. It is obviousthat these-elements maybe separate instrumentalities within thecontemplation of the invention.

As ,a feature of the inventirm,` the ,measureV maintained on the residuepassing through the line 84 is materially reduced or releasedaltogether, the valve 85 acting as a pressure reducing valve, wherebysubstantial separation of vapors due to latent heat takes place in theflash chamber 86. These vapors may be removed from, the chamber 86through the vapor line 81 controlled by valve 88, being introduced tothe interior of the dephlegmator 9 where they combine with the vaporsintroduced from the transfer line 56 directly from the reaction chamber55'..

As another feature of the present invention, in order to control thegravity and quality of the residue produced, Vwhich is particularlyimportant when the residue is to be sold commercially as a fuel oil,regulated portions of the crude oil may be diverted through the line 89controlled by valve 90 into the line 9| through line 92 controlled byvalve 93 into the residue draw of! header 16. It is to be noted that theinvention contemplates that the crude oil used for the pur- Vpose ofmixing with'the residue in the header16 may or may not be previouslypreheated, depending entirely on conditions of operation. However, topermit preheated crude oil to be diverted, I provide a branch 94controlled by valve 95 connecting respectively the pipes 35 and 9|. Incase it may be desirable to slightly cool the preheated crude oil beforeintroducing same to the residue draw off header 16, the valve 96 inleading to cooling coil 98 may be`l and by opening valve |02 may bedischarged into the residue draw off line 19 and passed to storage 83.Or the residue may be diverted from the lower line |0| into the line |03controlled by valve 04, cooled in cooling coil |05 and collectedrin anysuitable receptacle.

As another feature of it may be desirable in duce a maximum yield ofoverhead products, with little or no liquid residue. In other words, itmay be desirable to carry out what is termed a non-residuum process inwhich little or no substantial liquid residue is produced, the object ofthe process being to produce mainly a condensed overhead product and asubstantial nonilowing coke-like product. With such an operation it maybe further advisable to subject a portion of the liquid residuewithdrawn through the header 16 to conditions of flashing in the chamber86 in order to maintain the4 desired capacity. In such event the residuewithdrawn from the flash chamber 86 may be diverted through either orboth ofthe lines |06 controlled by valves V|01 merging in a commonreturn line |08, in which may be interposed a pump |09, returning saidresidue either to the transfer line 53 through the proper manipulationof the valve ||0 in the line or directly into the reaction chamber 55 byproper manipulation of the valve |2 in the branch ||3.

In addition to the methods of controlling the quantity or gravity of theresidue as described, a controlled quantity of the raw oil may bediverted through the line 4, passed through closed coil H5 positioned inthe vapor space of the present invention,l some operations to protheliash chamber 86 and controlled by the valves H6. By regulating theamount and temperature of the oil passing through the closed coil H5,the condensation or cooling of the vapors released in flash chamber 86may be definitely controlled. lIt will be obvious that the rcondensationof the vapors will directly control the quality and gravity of thenon-vaporous residue produced.

Reflux from the pool E2 which has been stripped of all the lightfractions may be withdrawn through the line H1 and mixed with the toppedcrude to be returned through the line 48 to the cracking zone.

The temperature and pressure conditions to be maintained on differentparts `of 'the plant Will depend entirely upon the operating'conditions, the type of charging stock used, and the products desired.It may be stated, however, that in the preferred form of the invention,the heating tube 5l and reaction chamber 55 are preferably maintainedunder a higher pressure than the dephlegmat-or I9 and flash chamber 8S.For instance, the pressure in the heating tube 5I and reaction chamber55 may be from 100 'to 33000 pounds, more o r less, while the pressureon the balance of the system may be materially reduced or even released,only carrying such a pressure as is necessary to overcome frictionalresistance.

From the foreg-oing it will be apparent vthat the invention has beencarefully worked out to provide a method of hydrocarbon oil conversioncomprising among other features, wide flexibility in operatingconditions, the use of charging stocks of wide ranges andcharacteristics, the production of maximum quantities of desiredproducts, coupled with the ability to be so manipulated as to becompletely reversed and produce maximum yields of entirely differentproducts.

I claim as my invention:

l. A process for converting hydrocarbons into lighter hydrocarbonscomprising subjecting the heavy hydrocarbons to cracking conditions oftemperature and pressure in a heating zone, separating the vaporous fromthe unvaporized liquid products, passing the unvaporized liquid productsto a distillation zone, materially lowering the pressure on theunvaporized liquid products delivered to said distillation zone toeffect distillation of the unvaporized liquid products in saiddistillation zone by the contained heat thereof, passing said vaporousproducts to a cooling zone wherein insufficiently cracked fractions arecondensed, also passing vapors released from the unvaporized liquidproducts in said contained heat distillation zone to said cooling zone,controlling the degree of cooling in said cooling zone and the degree ofdistillation in said contained heat distillation zone by circulatingheavy hydrocarbons being supplied to the process through said coolingZone and through said distillation zone, and subsequently supplying theheavy hydrocarbons so circulated to said heating zone.

2. A pr-ocess for cracking hydrocarbon oil, which consists in subjectingthe oil to cracking conditions of temperature and pressure in a heatingzone, separating the primary vapors from the unvaporized residue,effecting distillation of said residue by contained heat thereof underreduced pressure in a fiash distilling zone, subjecting said primaryvapors to a cooling treatment to condense insufficiently convertedfractions thereof, controlling the degree of said contained heatdistillation, and the degree of cooling of said primary vapors bycirculating heavy hydrocarbons being supplied to the process in heatinterchange relationship with the primary vapors and through said flashdistilling Zone, subsequently separating from said heavy hydrocarbonsthose constituents vaporizable 'at the temperature acquired by heatinterchange, collecting such constituents independently of yotherproducts of the process, and supplying the unvaporized heavyhydrocarbons to said heating zone.

l3. An oil cracking process which comprises heating the oil underpressure to a conversion temperature ina heating Zone, passing theheated oil to a conversion zone wherein a separation of vapors andunvaporized oil is effected, passing the vapors to a dephlegmating zone,removing said unvaporized oil from the conversion Zone and reducing thepressure thereon to effect a distillation thereof, cooling the vaporsevolved by such reduction in pressure by passing in heat exchangerelation therewith charging stock for the process, subsequentlyintroducing said vapors to said dephlegmating zone to commingle thereinwith the ir-st mentioned vapors, cooling the vapors in saiddephlegmating zone by heat exchange with charging stock for the process,stripping Yreflux condensate of entrained light fractions by indirectheat exchange with the rst mentioned vapors separated in sai-dconversion Zone, passing said charging stock and reflux condensate tosaid heating zone, and condensing the uncondensed vapors. Y

4. A cracking process Which comprises heating hydrocarbon oil tocracking temperature under pressure While flowing in a restricted streamthrough a heating zone, discharging the heated oil into an enlargedreaction zone maintained under cracking conditions of temperature andpressure, removing vapors and unvaporized oil from the reaction Zone andflash distilling the latter in a flashing Zone by pressure reduction,introducing resultant flashed vapors and the vapors removed from thereaction Zone into a dephlegmating zone and subjecting the same thereinto common fractionation to condense insufficiently cracked fractionsthereof, introducing fresh charging oil for the process into heatexchange relation with vapors in the dephlegmating zone, passing anotherportion of the charging oil in indirect heat exchange relation withvapors in the flashing zone, and subsequently supplying components ofsaid portions of the charging oil heavier than gasoline to said heatingzone.

5. A cracking process which comprises heating hydrocarbon oil tocracking temperature under pressure while flowing in a restricted streamthrough a heating zone, discharging the heated oil into an enlargedreaction zone maintained under cracking conditions of temperature andpressure, removing vapors and unvaporized oil from the reaction zone andash distilling the latter in a flashing zone by pressure reduction, in-

troducing resultant flashed vapors and the va-V pors removed from thereactions zone into a dephlegmating Zone and subjecting the same thereinto common fractionation to condense insufflciently cracked fractionsthereof, passing crude oil containing desirable light fractions inindirect heat exchange relation with hydrocarbon constituents in theflashing zone thereby supplying heat to the crude oil and controllingthe degree of distillation in the flashing zone, Vaporizing said lightfractions from the crude oil and condensing and collecting the same, andsupplying heavier portions of the crude oil in admixture with refluxcondensate from the dephlegmating zone to said heating Zone.

6. A cracking process which comprises heating hydrocarbon oil tocracking temperature under pressure While fiowing in a restricted streamthrough a heating zone, discharging the heated oil' into an enlargedreaction zone maintained under cracking conditions of temperature andpressure, removing vapors and unvaporized oil from the reaction zone andash distilling the latter in a flashing zone by pressure reduction,introducing resultant flashed vapors and the va.- pors removed from thereaction zone into'a dephlegmating zone and. subjecting the same there-Vin to common fractionation to form a composite reux condensate ofheavier fractions of the flashed vapors and insuicientlycraokedefracrtions of the first-named vapors, passing crude oil inindirect heat exchange relation with the vapors undergoing commonfractionation in the dephlegmating zone and heating the same todistillation temperature, introducing the heated crude oil into atopping and fractionating zone apart from said dephlegmating zone andtopping and fractionating the same therein independently of the vaporsinthe dephlegmating Zone to separate lighter Yfractions thereof asvapor, finally condensing and collecting these vaporized lighterfractions of the crude, combining heavier fractions of the crude withcomposite reflux condensate from the dephlegmating zone and supplyingthe resultant mixture to the heating Zone, and

finally condensing and collecting the vapors uncondensed in thedephlegmating zone independentlyv of said vaporized lighter fractions ofthe crude. Y

7. A conversion process which comprises subjecting hydrocarbon oil to,crackingV conditions of temperature and pressure in a cracking zone,removing vapors and unvaporized oil from the cracking zone,simultaneously topping and fractionating crude oil in a topping andfractionating Zone to separate light fractions from heavier fractionsthereof recovering the light fractions, combining a portion ofthevheavier fractions of the crude with said unvaporized oil anddistilling the resultant mixture in a'flashing zone maintained underlower pressure than the cracking zone, fractionating vapors from theflashing zone independently of the crude oil in said topping andfractionating zone and in admixture with the first-named vapors in adephlegmating zone apart from said topping andy fractionating zone toform a composite reflux condensate, supplying such reflux condensatetogether With'another portion of the heavier fractions of the crude tothe crack-r ing zone, and finally condensing the fractionated vapors. Y

8. The process as defined in claim 4 further characterized in that thefirst-named charging oil is passed in indirect heat exchange relationwith vapors in the dephlegmating zone.

Y CARBON P. DUBBS.

